Electrical means and method of remote control



April 12, 1938- P. N. SMITH 2,114,062

ELECTRICAL MEANS AND. METHOD OF REMOTE CONTROL Filed Oct. 5, 1933 5Sheets-Sheet l w 2 5m g; EFL a M a PM g; E o Hu NFL Fe -L R? a N. E E

April 12, 1938. P. N. SMITH 2,114,062

ELECTRICAL MEANS AND METHOD OF REMOTE CONTROL Filed Oct. 5, 1933 5Sheets-Sheet 2 April 12, 1938. I P. N. SMITH 2,114,062

ELECTRICAL mums AND mmnon 0F REMOTE CONTROL Filed Oct. 5, 19s: 5Sheets-Sheet s F ic i P.Pt SNHTPI ELECTRICAL MEANS AND METHOD OF REMOTECONTROL 5 Sheets-Sheet 4 Filed Oct. 5, 1933 I fix April 12, 1938. P. N.SMITH 2,114,062

ELECTRICAL MEANS AND METHOD OF REMOTE CONTROL Filed Oct. 5, 1933 5Sheets-Sheet s Fiq.

I r- 3a5 PM. fizw Patented Apr. 12, 1938:

uN-irEo STATES eA'rENT OFFICE ELECTRICAL MEANS am! run-mop or REMOTEcou'rmr.

Philip Norman Smith, Meir-ole, Macs. Application October 5, 1933, SerialNo. 892,8

28 Claims.

This invention relates to a method and means for'the remote control ofelectrical circuits and more particularlyto those cases where it isdesired to control a largenumber of circuits at a distance in thesimplest possible manner.

It is the object of the present invention to provide such a method andmeans and, also to provide a new method and means for the transmissionover short or long distances and by wire or radio means of typewrittencharacters or the like.

In the accompanying drawings 1 Figure 1 is an elementary schematicdiagram to illustrate the functioning of one part of my invention:Figure 2 is a modification of the schematicwiring diagram shown inFigure 1;

Figure 3 shows a wiring diagram of a remote control circuit for directcurrent operation;

Figure 4 shows a detail drawing of the shortcircuiting contact;

Figure 5 shows still another modification of my invention;

Figures 6 and 7 show other modifications of the system; 25 Figure 8shows a detail of the selector hardepressor;

Figure 9 shows a diagram of the essential features of a modification ofmy invention for transmitting teletype messages using direct current;

30 ,QFigure 10 shows a detail of the keybar selector switch Fi'gurellfshows the same system as Figure 9 but modified to use alternatingcurrents 'for radio and long wire circuits which will hereinafter bedescribed in detail.

More particularly this invention utilizes the ability of twoelectrically controlled and pivotally connected pantograph arms ofassuming at their common point, a relation with respect to some 40 otherfixed point which is determined by the currents supplied to them, toselect for energization one or more of a number of electrical circuitsat the will of the operator, from the point fromwhich the controllingcurrents are sent.

The increasing use of methods for controlling industrial operations froma distance without the necessity of an operator being actually presentat the point at which the operations are taking place,

is suflicient proof that there is a definite place in 50 industry for asimple apparatus which will make possible the control of a number ofoperations from a distance. Obviously the number of such operationswhich can be controlled from a distance with little or no increase inthe complexity 55 of the equipment will be a measure of its utility.

The distant control of electrical generating. plants and substations,the remote control of radio transmitters, radio ship beacons andaviationsbeacons,the teletypeby means of which typewritten characterscan betransmitted to and re- 5 produced at a distant point. are a fewexamples of the diverse fields in which remote control equipment finds aplace.

Some of the methods known to the art for the i remote control of theabove services involve the 10 transmission, by wire or radio means andif the' number of conductors or circuits between the two points is to bekept to a minimum, of a series of impulses of various lengths orgroupings which impulses or groups are transformed through some 15selecting means into the action which it is desired to produce. Thus inthe so-called "five unit? teletype system the various charactersrequired in transmitting typewritten messages are obtained by variouscombinations of impulses in the five 20 unit" group.

Meter readings and so forth from power stations are transmitted to acontrol point by various methods some of which involve the use ofimpulses, some the use of different frequencies and so on. All of thesemethods become cumbersome however when any great number of operationsare to be controlled. There is therefore a distinct demand for a controlequipment flexible enough to cover a large number of operations with noadded complexity in itself on that account and which does not depend onaccurate timing, a large number of control frequencies, impulses orcircuits for its positive and accurate action.

This invention meets these requirements in a simple and effectivefashion as the following, explanation of its operation will show.

In order to understand the principle of this invention reference shouldbe made to the diagram shown in Figure 1. In this diagram I is a sourceof electrical power and maintains a constant voltage across therheostats 2 and 3. 4 and 5 are short electrically conducting arms of twobell cranks the longer arms of which (6 and 1) are pivotally connectedto the rigid arms 8 and 9 45 which arms are also pivotally joined attheir other ends at a common point In.

It will be clear from the above that as the com-.- mon point In is movedto various points on the tablet ii, the voltages between ground and' theconducting arms 4 and 5 of the bell cranks which make contact with therheostats 2 and 3. will vary depending upon the position of the junctionpoint Ill on the tablet ll.

Suppose now that at some other point which will be designated as thereceiving station, a similar pair of bell cranks are provided and whichalso have pivotally interconnected rigid arms.

Suppose also that the shorter arms of this second pair of bell cranksare pivotally connected to movable coils I4 and I6 disposed in the mag-'netic fields provided by the magnets I6 and I7, instead of to therheostats as was the case at the transmitting station.

Suppose further that the varying voltages between the bell crankconducting arms and ground at the transmitting station are carried bywires I2 and I3 to one end respectively of coils I4 and I6 while theother ends of these coils are connected to ground.

The varying voltages set up between wire I2 and ground and between wireI3 and ground will cause correspondingly varying currents to flowthrough coils I4 and I6 respectively and, since these coils aresupported in the permanent magnetic fields provided by the magnets I6and I I they will assume a position which will depend upon themagnitudes of the currents traversing them. The movements of these coilsI4 and I5 will as a consequence cause movements in arms I8, I9, 20, and2I with the final result that the common point 22 of rigid arms 20 and2| will execute with respect to tablet 23 the same movements that commonpoint III in the transmitter executes with respect to its tablet II.Thus if the operator at the transmitting station wishes to have thejuncture point 22 assume some position as A on the tablet 23 it willonly be necessary for him to move the common point I0 at the transmitterto the corresponding position A on the transmitter tablet II and thedesired position A will be automatically achieved.

Similarly it he wishes to have point 22 assume other position such as Bor C it can be automatically accomplished bymoving point I 0 to thecorresponding positions B and C' on tablet II.

It will be clear from the above that point 22 can be made to assume anydesired position on the tablet 23 by moving point III to thecorresponding position on tablet II. It will also be clear that theactual mechanical movement 01. point I0 and the simultaneous movement ofarms 4 and 5 on the rheostats 2 and 3 on this account in order to bringabout changes in the position oi! point 22 are unnecessary, providingthat voltages corresponding to the desired position of 22 aretransmitted to coils I4 and I5.

In other words it is possible to have point 22 assume any one of anumber of positions on tablet 23 without the necessity of using asimilar pantograph system at the transmitter, by providing means forobtaining and transmitting to coils I4 and I5 the voltages needed tomake point 22 assume the desired position.

Figure 2 illustrates a method of doing this. Resistors 24, 26, 28, 30,32 and 34 are connected in series across a source of voltage I andsimilarly resistors 25, 21, 29, 3|, 33 and 35 are also connected inseries across the source of voltage I. The values of the resistors areso chosen that when the contacts of switch 36 are closed the voltagesapplied between ground and wire I2 and between ground and wire I3 aresuch as to cause currents to flow in coils I4 and I5 which will assurethat point 22 will assume position A for instance on tablet 23.

Similarly when switch 31 is closed the voltages applied between groundand wire I2 and between ground and wire I3 may be made such as to causecurrents to flow through coils I4 and I5 which will It will beunderstood that although only six positions of point 22 are shown thesame method can readily be extended-to include as manypositions as maybe desired by providing the additional necessary resistors and switches.

Figures 3 and 4 indicate how the above described methods tor movingpoint 22 to any desired position can be utilized in a practical circuitselector. Tablet 23 in Figure 3 can conveniently take the form of ahorizontally disposed panel of some insulating material such asBakelite. At points A, B, C, D, E, and F are provided pairs ofelectrically conducting segments which are supported by the panel 23.

Furthermore an insulated piece 46 shown in detail in Figure 4 isprovided and is disposed at the juncture point of arms 20 and 2i. Theindividual segments 46 and 5| in Figure 4 are insulated from each otherby an insulating segment 43 and are so spaced from one another that whenthe conducting piece 41 at the junction of arms 20 and 2| takes aposition such as is shown in Figure 4 and is brought down on any pair ofsegments, an electrical circuit is established between them which isagain interrupted when the conducting piece 41 is raised.

The insulating panel 23 carrying the pairs of segments oi. which onepair is provided for each circuit to be controlled, and the two arms 26and 2I are bridged by a yoke 43 which yoke in turn is connectedmechanically to a coil 52 movably supported in the magnetic fieldprovided by magnet 53 as shown in Figure 3. When a current of the properstrength traverses coil 52 and in the proper direction the yoke 43 isdrawn down and forces the insulated piece 46 carrying conducting member41 down against the panel 23 at whatever point piece 46 happens to be atthe time when coil 52 is energized.

In order to efiect this action of yoke 43 the switches 36, 31, 36, 39,40 and 4i. in Figure 3 in addition to having contacts connected toresistances 24, 25, 26, 21, 26, 29, 30, 3I, 32, 33, 34 and 35 are alsoeach provided with a set of contacts connected in series with coil 62,battery I and ground so that whenever any one of the switches 36, 31,38, 33, 4l'or 4I are closed the extra pair of contacts in series withcoil 52 is also closed but only subsequent to the closure of the twopairs of contacts connected to the resistors controlled by that switch.By arranging the respective closures in this way, time is allowed forthe interconnected pantograph arms to come to rest before piece 41 isdepressed to close the circuit between the segments of a. pair.

The closure of the circuit between segments of a pair provided by thedepression 01 member 46 can then be used to energize a relay whosecontacts are connected in the circuit which it is desired to control.This energization of the circuit in question will continue as long ascoil 52 is energized which in practice would mean as long as one of theswitches at the transmitter is depressed. As soon as the switch key atthe transmitter is released the various circuits at the receivingstation will be deenergized and member 46 will be returned to itsinitial position of rest at the left by spring 32.

IFwill be noted from a study of the foregoing that the position ofmember 46 is dependent upon the values of the currents in the two coilsI4 and I5. It will also be evident that if the currents to the two coilsI4 and I6 should for some reason or other suiler a reduction intransmission due to line losses or other causes so that the currentswhich actually traverse these coilsis less than was intended theposition of member 46 as a result of the flow of these-currents in theactuating coils might not be the one desired which might mean that someother circuit than the one intended would actually be energized atthe-receiving station.

To guard against this possibility a test circuit has been provided whichis as follows.

One set of switch contacts is provided at the transmitter which whenclosed under normalconditions will ensure that member-'46 at therecelving station will take some position such as A on panel 23. The twosegments of'the pair at A may be connected through wires l2, l3, battery'II and ground to an annunciator or other suit- I able signaling deviceat the transmitting station.

- factorily. If the operator at the transmitter does been shownalthoughthe number of not receive the expected return signal he can then takethe necessary steps to locate the cause of the diihculty and correct it.

In all the foregoing description reference has continually been made tothe use of pantographarms at the receiving station and to the use ofvarious resistances at the transmitter to control the actuating currentto these arms and consequently the movements of the arms themselves.Although the use of two pantograph arms for controlling the position ofmember 46 is highly advantageous in a number of cases, It will sometimeshappen that a system such as is illustrated in Figure will besuilicient.

In the system illustrated schematically in Figs ure 5 the pairs ofsegments which may be short circuited by the conducting piece carried bymember 46 are disposed around the arc of a circle, whose center isalso'the axis IOI about which arm I00 is'pivotedand free to move underthe influence of the force exerted by coil I02 which is movablysupported in the field of magnet I03. The arm I00 which supports member46 is returned to its position of rest at the extreme left by the actionof a coil spring or, as in the case shown in Figure 5, may be returnedto its positionof restby a combination of a spring and an electromagnetor even by electromagnetic means alone. Rigid member I06 pivoted-aboutaxis I04- has one end which may be made arcuate in form so as to ensurethat in any position of arm I00 it may be pulled up by the action ofmagnet I06 on'armature I06 and thereby depress rigid arm I00 so thatconducting member. 41 on its outer end may short circuit the desiredpair of segments.

Reference to Figure 6 will illustrate the electrical connections of thesystem where for simplicity sake two points only on the selector have itwill be understood that circuits which can be controlled in this way isby no means-so limited. Switches HI and I22 which are individuallycapable of selecting one circuit each at the receiver for energizationare each provided with two pairs of blades; one being the pair usedtointroduce the proper resistance into the circuit completed bysource'of power I20, wires I20 and I24 andr'nagnet coil I02 so that armI 00 will assume some desired position at the receiving station, and theother pair of blades being used, after arm I00 has taken up the desiredposition, to depress arm I00 thereby completing the desired circuit.

With reference to the switches used at the transmitter it will beunderstood that although the foregoing has more particularlyreferred tothe use of switches which will delay the actuation of coil I06 untilafter arm I00 has reached the desired position, the use of such switchesas are illustrated is merely for convenience and that the same resultcan .be obtained by the use of time delay relays connected as shown inFigure 7 to ensure that circuit energization at the receiver will nottake place until the individual seg-.

ments of a pair have been short circuited for the proper length of time.

Under such circumstances as have just been outlined the use of anarm-depressing circuit between the transmitter and receivercan bedispensed with as may also member I08 in Figure 5 and its associatedsupportingpiece together with magnet I05 shown in Figure 8. Figure '7illustrates the circuit sorevised where I25 and I26 are time delayrelays which will not close their respective circuits until theindividual segments of the pair of contacts at the receiving stationcircuit selector with which they are connected in series will have beenshort circuited for the proper length of time by the short circuitingpiece carried on the end of arm I00.

It will be understood that in this particular arrangement the conductingsegments of each pair of eontactson the insulating panel I0I (Figure 5)maybe made flush with the surface of the panel so that the shortcircuiting member at the end of arm I00'may be in contact with thesurface of the panel at all times and need not be slightly removed fromit as would be the case where a depressor mechanism is employed.

It will be clear from the foregoing that my inventionis of great utilityand susceptible to application in a number of different fields whichwill readily occur to those skilled in the art. For instance the sametype of mechanism. at the receiving station maybe used for controllingpurely mechanical operations such as closing or opening valves and thelike without departing from the spirit of my invention. In the caseswhere purely mechanical operations are to be controlled the depressionof the arm may be used to effect the operation directly without thintervention of an electrical circuit.

. One of the purposes of this invention is to provide a more convenientand simple means for the transmission and reception of so called"teletype messages wherein typewritten messages can be transmitted toand reproduced at a distant point. Most of the systems now known and inuse for this purpose involve the transmission of .various impulses orgroups of impulses which impulses are used upon their arrival at thereceiving station and after passing through a selector mecha-- nism toactuate the keybar carrying the letter or character which it is desiredto reproduce.

The best known of these systems is the so called five uni teletype wherethe transmission of any desired letter is effected by transmi tingvarious combinations of impulses and spaces in the five unit group. Thissystem while comparativeiy effective is open to a number of obj cc"-tions among which are that .it requires synchronization between thesender and receiverw ichis frequently diflicult to'obtain andfurthermore that it requires very complicated and expensive apparatus atboth the sending and receiving stations.

My invention involves no such difficulties and in fact it can beattached to a standard typewriter without any but minor alterations tothe typewriter itself. To learn how this may be done in a simple mannerreference should be made to Figure 9 where l is a source of power. oneside of which is grounded and the other side of which is connectedthrough wire 220 to switch blades 200, 201,2l0, 2H, 2 and 210. Whenswitch contacts 200 and 200, 200 and 2", or 213 and.2l4 are closed acurrent whose magnitude depends on which switch is closed, fiows throughwires 220 and 22| and thence through coil 2" which is movably supportedin the magnetic field provided by magnet 2l0..- This current flow causescoil 210 to move and thereby moves arm-224 to some position over a pairof segments. Closure of contacts 201 and 200, 2 and 2l2, or 2l0 and 2"energizes coil 2 and as previously explained depresses arm 224 causingthe conducting member at its end to short circuit the segments overwhich it happens to lie. In the actual equipment two pairs of switchcontacts together with an armature are pivotally attached to each key ofthe typewriter as illustrated in Figure 10 which shows a detail sketchof the keybar and switch contacts 200 and 200, and 201 and 200. When thekey is depressed contacts 200 and 200 close first which causes arm 224to assume some given position determined by the voltage of the source iand the resistance 202. Further pressure on the key results in theclosure of contacts 201 and 200 which energizes coil 2" and depresses am224 and for example if the current in coil 2" is such as .to make bar224 take a position over pair of segments 220, then energizes relay 226.The current caused thereby to fiow through coil 221 creates a pull onarmature 230 which, acting through rigid member 220 and the short arm ofthe bell crank typebar 220 pivoted at 232, depresses the typebar andprints the desiredletter at the receiving station.

Similar pairs of switch blades are provided for each operation orcharacter which it is desired to transmit. Upper or lower casecharacters may be transmitted as with the ordinary teletypewriter.

' The operation of the carriage shift mechanism is effected in asomewhat different way. The operator at the transmitter upon reachingthe end of a line will of necessity operate the carriage return inpreparation for the next line. In order to accomplish the same result atthe receiving station an extra key is provided at the transmit- .terwith two sets of contact blades similar to the other keys. When this keyis depressed the short circuiting member carried on the end of arm 224short circuits the segments 233 thereby energizing relay 234 andapplying power to motor 235 from power supply 230. This motor throughthe medium of a pinion on its shaft moves rack 230 over and consequentlythe carriage of the receiving typewriter to its extreme right handposition. A limit switch 231 is provided in series with which is themotor 235 so that the motor will be cut off as soon as it hasaccomplished the return of the carriage even though the carriage returnkey at the transmitter may still be depressed.

It will be noted in Figure 10 that a solenoid coil has been providedaround the armature on the end of the switch contact bar. It is thiscoil which makes it possible to use the same typewriter for transmittingand receiving assuming of course that the movable arm and its associatedmechanism and circuits are also provided at the transmitter. When it isdesired to make the same machine available for either sending orreceiving the coil surrounding the armature on the end of the contactbar in Figure 10 will be connected into the circuit in the positiontaken by coil 221 in Figure 9. Each of the coils on the remainingkeybars will -be similarly connected through a relay to a pair ofsegments on the receiving panel.

It will be immediately apparent that the only remaining equipmentrequired will be a triple-pole double throw switch to throw theequipment from a sending condition to a receiving condition or viceversa with respect to the line wires HI, and 222. A test circuit such ashas been described before is also provided consisting of the seriescircuit made up of annunciator 24l,'wire 223,

source of power 240, contacts 242 and ground. Direct current circuitssuch as have been described exclusively in the foregoing are entirelysatisfactory for short distance transmission. For longer distances overwire or radio circuits the use of alternating current becomesimperative. My invention is not confined to use on direct currentcircuits but may with ease be applied to long distance wire or radiocircuits equally well. Figure 11 shows a wiring diagram in suillcientdetail to explain the system, of a typical arrangement of my inventionfor use in transmitting teletype messages over long distance wire orradio circuits. It will be noted that the general arrangement ofcircuits in the alternating current case is similar in many respects tothe direct current cases heretofore discussed except that certainchanges which, in order to overcome exigencies inherent in radiocircuits, I have found it desirable to incorporate.

Referring to Figure 11 it will be noted that when the double pole switch001 which is similar in all respects to the key switches shown in Figure9, is depressed the first action is to allow 1000 cycle current in anamount which is determined.

by resistor 304 and the voltageof the source, to fiow through one of theprimary windings of the transformer 300. From thence it may betransmitted by any of theusual wire or radio means to the receiver. Atthat point it is filtered out by a simple tuned circuit, amplified,rectified and allowed to fiow through the windings of coil "0 therebycausing arm 224 to assume some particular desired position with respectto the row of pairs of segments over which it passes.

contacts to close which applies a 666 cycle voltage to the primary oftransformer 300 which voltage is similarly transmitted to the receiverwhere it is filtered out, rectified, and applied to coil 2, whichresults in arm 224 being depressed and the desired circuit at the.receiver energized. Arm 224 it will be noted is returned to itsposition of rest by means of a spring which is secured at Furtherpressure on switch 301 causes the other pair of ceive. together with anamplifier as shown.

.awheu' switch as is closed a 444 cycle voltage is transmit applied tothe primary of transformer 808 and is to the receiver where it isfiltered out, amplified, rectified and allowed to flow through coil ii.In so doing of course it applies a pull to the arm 224 through spring320 which together with the tension of the spring tends to return thearm I to its position of rest. Under ordinary circumstances the tensionon the arm produced by this combination will then bezmade up of twoparts; one part being the constant pull or the coil due to the currenttraversing its windings and the other being the variable tensionsupplied by the spring which will be a function of the displacement ofarm "4 from its position of rest.

In ordinary practice the 444 cycle frequency will be transmittedcontinuously as long as transmissions are to be eflected. The number of666 cycle emissions and the number and intensity of the 1000 cycleemissions will of course depend upon which keys are depressed and howfrequently. I

The advantage of having one end of the armreturn spring attached to thecell which derives its pull from a rectified alternating currentreceived through the same channel as the 1000 cycle current used tocontrol the position of the arm is immediately obvious.

all transmitted together and filtered out at the receiver, staticdisturbances received along with the signal affect the 1000 cycle, 666cycle and 444 cycle circuits nearly equally. Such disturbances will bepassed on through the amplifiers, rectified and passed through the twocoils BIB and 9 along with the currents from .the signals. Any forcesset up by the passage of these rectified stray currents through coils 3l8 and 3l9 will balance each other out insofar as movementof arm I isconcerned so that this member is substantially free from interference,within the capacity of the amplifier, due to stray currents.

As will be seen from Figures 8 and 11 a similar plan is used to protectthe 666 cycle or depressor circuit from extraneous electricaldisturbances, rectified current from the 444 cycle channel being passedthrough the winding of coil "I which coil when traversed by rectifiedstray currents, will provide the necessary force to counterbalance anyunwanted movements of the depressor arm when coil 2" is also traversedby rectified stray currents.

The many advantages of my invention will be readily apparent to thoseskilled in the art. What I claim and wish to secure by Letters Patentis:

1. A method of reducing the efiect of extraneous electrical disturbanceson electrically controlled mechanical movements consisting of providingat least one voltage, varying this voltage in accordance with themechanical movement which it is desired to produce, providing a secondvoltage, transmitting these voltages to a distance, converting them intoforces and utilizing the algebraic sum of said forces, at the receivingpoint to eifect the movement desired and to reduce the etlect on saidmovement of equal changes in the magnitudesof said forces.

2. A method of determining which mechanical movements are produced at adistance comprising providing a voltage, varyin the intensity of thisvoltage in accordance with a desired movement, transmitting this voltageto a distance, converting it into a mechanical movement at the receivingstation and, by the completion of said movement, effecting anotification to the station from which said voltage was transmitted,when said movement coincides with the movement which it is desired toproduce.

3. An apparatus for controlling electrical circuits at a, distancecomprising means for selecting from a plurality of voltages individuallyadjusted in accordance with circuits which itmay be desired to control,a voltage in accordance with the circuit which it is desired to control,means for controlling a second voltage in accordance with the time atwhich control of the selected circuit is desired, means for'transmittingthese voltages to a distance, means for converting one of saidtransmitted voltages into a current and converting said current into arotatory mechanical movement at the receiving station to effect theselection of the desired circuit and electrically separated meanscooperating with the other voltage to eflect the control of the selectedcircuit.

4. A method of controlling electrical circuits at a distance comprisingproviding a plurality of voltages individually adjusted in accordancewith the circuits which it may be desired to control, selectingindividually at least one of these voltages in accordance with thecircuit which it is desired to control, transmitting it to a distance,converting it into a current and converting said current, whilemaintaining/ it constant in direction and magnitude, into a rotatorymechanical movement in accordance with the circuit desired at thereceiving point to effect the selection and control of the desiredcircuit.

5. A method of controlling electrical circuits at a distance comprisingproviding a plurality of voltages individually adjusted in accordancewith the circuits which it may be desired to control, selecting one ofthese voltages in accordance with the circuit which it is desired tocontrol, transmitting it to a distance, converting it into a current andconverting said current, while maintaining it constant in direction andmagnitude, into a rotatory circuit completing mechanical movement inaccordance with the circuit desired at the receiving station to effectthe selection and control of the desired circuit.

6. A method of controlling electrical circuits at a distance comprisingproviding a plurality of voltages individually adjusted in accordancewith the circuits which it may be desired to control, individuallyselecting at .least one of these voltages,,transmitting it to adistance, converting it into a current and converting said current,while maintaining it constant in direction and magnitude, into arotatory mechanical movement at the receiving point in accordance withthe circuit desired to effect the selection of the desired circuit andits control a definitely desired time interval thereafter as a result ofsaid selection.

'7. A method of controlling electrical circuits at a distance comprisingproviding a plurality of voltages individually adjusted in accordancewith the circuits which it may be desired to control, individuallyselecting at least one of these voltages in accordance with the circuitwhich it is desired to control, providing a second voltage, contheaccuracy with 1 troll ing this voltage in'accordance with the time.

ra.lity ...ot voltages individually adjusted in accordance with thecharacters which it may be desired to transmit, individually selectingat least one of these voltages in accordance with the character which itis desired to transmit, transmitting this voltage to a distance,converting it into a current and converting said current without changein direction or magnitude into a rotatory mechanical movement at thereceiving station in accordance with said current to eflect theselection and production of the desired character.

9. An apparatus for controlling electrical circuits at a distancecomprising means for selecting from a plurality of voltages individuallyad- Justed in accordance with the circuits which it may be desired tocontrol, at least one voltage in accordance with the circuit which it isdesired to control, means for transmitting this voltage to a distanceand means for converting it into a current and converting said current,while maintaining it constant in direction and magnitude, into arotatory mechanical movement at the receiving point in accordance withsaid current to eiIect the selection and control of the desired circuit.

circuits at a distance, output terminals, means for selecting from aplurality of voltages individually adjusted in accordance with circuitswhich it may be desired to control, at least one voltage in accordancewith the circuit which it is desired to control, means for delivering itto certain 01' said output terminals, and means for delivering inaccordance with the time at which control of the selected circuit isdesired, voltage to other of said output terminals.

11. In an apparatus for controlling electrical circuits at a distance,an input circuit and means associated therewith influenced by currentreceived through said input circuit for eflecting the selection of adesired circuit by a rotatory movement in accordance with said currentand its control by the unchanged flow in direction or magnitude of saidcurrent.

12. In an apparatus for controlling electrical circuits at a distance,an input circuit, an electrical connecting element, and means associatedtherewith influenced by current received through said input circuit forbringing about a rotatory mechanical movement of said electricalconnecting element in accordance with said current'to effect theselection of a desired local circuit and its cm/ntrol by the flowunchanged in direction or magnitude of said current.

13. In an apparatus for controlling electrical circuits at a distance,delayed action circuit controlling means, an input circuit, and meansassociated therewith influenced by current received through said inputcircuit for bringing about a rotatory mechanical movement in accordancewith said current for selecting local circuits in accordance with saidcurrent and e'iIecting the control at a definite desired time intervalthereafter 0! the local circuit so selected, through the medium of saiddelayed action circuit controlling means as a result or said selection.

14. In an apparatus for controlling electrical circuits at a distance,input circuits and means associated with one of said circuits influencedby current received through it for bringing about a rotatory mechanicalmovement for selecting local circuits in accordance with said currentand means electrically distinct from said first means cooperating withand influenced by current .received through another input circuit foreffecting control of the selected circuit.

15, An apparatus for reducing the effect 01 extraneous electricaldisturbances on electrically controlled mechanical movements, comprisingin-' put circuits, means associated therewith tor executing mechanicalmovements in accordance with current received through at least one ofsaid input circuits and means, including a restraining means,cooperating with current received through another input circuit foropposing the movements of said movement executing means so as to reducethe eflect on said movement executing means, of equal changes in themagnitudes of the currents received through these two input circuits.

16. In an apparatus for producing printable characters at a distance,typebars, paper feeding means associated therewith, local circuitscontrollingsaid typebars, an input circuit and means associatedtherewith influenced by current received through said input circuit forbringing about a rotatory mechanical movement for individually selectingsaid local circuits in-accordance with said current and controlling saidcircuits through the flow of said current while it is being maintainedconstant in direction and magnitude.

17. In an apparatus for eflecting the remote control of a typewritercarriage, an input circuit, means associated with said input circuitactuated by current received through it for bringing about a rotatorymovement in accordance with said current for selecting and controlling alocal circuit and means included in said circuit for effecting the throwof said carriage when said local circuit is completed.

18. In an apparatus for effecting the remote control of a typewritercarriage, an input circuit, means associated with said input circuitactuated by current received through it for bringing about .a rotatorymechanical movement in accordance with saidcurrent for selecting andcontrolling a local circuit and means included in said circuit forefiecting the throw of said carriage including means for deenergizingsaid carriage moving means at the completion of the throw, when saidlocal circuit is completed.

19. A method of controlling electrical circuits at a distance comprisingproviding a plurality of alternating current voltages individuallyadjusted in accordance with the circuits which it may be desired tocontrol, individually selecting at least one of these voltages inaccordance with the circuit which it is desired to control, transmittingit to a distance and converting it into a unidirectional current andconverting said current, while maintaining it constant in direction andmagnitude, into a rotatory mechanical movement at the receiving point toefiect the selection and control of the desired circuit.

20. A method of controlling electrical circuits at a distance comprisingproviding a plurality of alternating current voltages individuallyadjusted in accordance with the circuits which it may be desired tocontrol, individually selecting at least one of these voltages inaccordance with the circuit which it is desired to control, providing asecond alternating current voltage of a diiierent frequency, controllingthis voltage in accordance with the time at which control of theselected circuit is desired, transmitting these voltages to a distanceand converting them into unidirectional currents and converting saidcurrents into electrically distinct mechanical movements at thereceiving point to eflect the selection and control of the desiredcircuit.

21. A method of controlling electrical circuits at a distance comprisingproviding a plurality of alternating current voltages individuallyadjusted in accordance with the'circuits which it may be desired tocontrol, selecting one of these voltages in accordance with the circuitwhich it is desired to control, transmitting it to a distance andconverting it into a unidirectional current and converting said currentinto a circuit completing rotatory mechanical movement at the receivingstation to efiect the selection and control oi! the desired circuit.

22. A method of transmitting printable characters to a distancecomprising providing a plurality of alternating current voltagesindividually adjusted in accordance with the characters which it may bedesired to transmit, individually selecting at least one voltage inaccordance with the character which it is desired to transmit,transmitting this voltage to a distance and converting it into aunidirectional current and converting said current into a rotatorymechanical movement at the receiving station to effect the selection.and production of the desired character.

23. An apparatus for controlling electrical circuits at a distancecomprising means for selecting from a plurality of alternating currentvoltages individually adjusted in accordance with the circuits which itmay be desired to control, at least one alternating voltage inaccordance with the circuit which it is desired to control, means fortransmitting this voltage to a distance and means for converting it intoa unidirectional current and converting said current without change indirection or magnitude into a rotatory mechanical movement at thereceiving point to effect the selection and control oi'the desiredcircuit.

24. In an apparatus for controlling electrical circuits at a distance,an input circuit adapted to the receipt of alternating current voltages,means for converting said voltages into unidirectional currents inaccordance with said voltages, an electrical connecting element, andmeans associated therewith influenced by said unidirectional currentreceived through said input circuit for bringing about a rotatorymechanical movement of said electrical connecting element to efiect theselection or a desired local circuit and its control.

25. In an apparatus for reproducing printable characters at a distance,typebars, paper feeding means associated therewith, local circuitscontrolling said typebars, an input circuit adapted for the receipt ofalternating current voltages, means for converting said voltages intounidirectional currents in accordance with said voltages and meansassociated with said unidirectional currents influenced thereby forbringing about a rotatory movement for individually selecting said localcircuits in accordance with said current and controlling said circuitsby said current.

26. A method of transmitting printable characters to a distancecomprising providing a plurality of voltages individually adjusted inaccordance with the characters which it may be desired to transmit,individually selecting at least one of these voltages in accordance withthe character which it may be desired to transmit, providing anothervoltage, controlling this voltage in accordance with the time at whichreproduction of the selected character is desired, transmitting thesevoltages to a distance, converting them into currents and convertingsaid currents into electrically separate mechanical movements at thereceiving point to efiect the selection and reproduction of the desiredcharacter.

27. A method of transmitting printable characters to a distancecomprising providing a plurality of voltages individually adjusted inaccordance with the characters which it maybe desired to transmit,individually selecting at least one oi these voltages, transmitting itto a distance, converting it into a current and converting said currentinto a rotatory mechanical movement at the receiving point in accordancewith the character desired to eifect the selection of the desiredcharacter and its reproduction a definitely delayed time intervalthereafter as a result of said selection.

28. In an apparatus for controlling electrical circuits at a distance,an input circuit adapted to the receipt of an alternating currentvoltage, means for converting said voltage into a unidirectional currentmeans associated with said unidirectional current and influenced by itfor bringing about a rotatory mechanical movement for efiecting theselection of the desired circuit in accordance with said current and itscontrol by the flow oi said current while it is being maintainedconstant in direction and magnitude.

PHILIP NORMAN SMITH.

